package com.kotlin.lib

import java.lang.IllegalStateException
import kotlin.contracts.contract


fun require(condition: Boolean) {
//    contract { }
    if (!condition)
        throw IllegalStateException("....")
}

fun fool(s: String?) {
//    require(string == null)

//    println(s.length)
}


fun main() {
    println("-----------")
//    fool("abc")

}